Specifies the distance you want the drop shadow to be offset
from the object.

Blur

Specifies the distance from the edge of the shadow where
you want any blurring to occur. Illustrator creates a transparent
raster object to simulate the blur.

Color

Specifies a color for the shadow.

Darkness

Specifies the percentage of black you want added for the
drop shadow. In a CMYK document, a value of 100%, used with a selected
object that contains a fill or stroke color other than
black, creates a multicolored black shadow. A value of 100% used
with a selected object that contains only a black fill or stroke
creates a 100% black shadow. A value of 0% creates a drop shadow the
color of the selected object.